Method for preparation of pharmacologically-relevant compounds from botanical sources

ABSTRACT

In a multi-step process for selectively purifying various pharmacologically-relevant components of a source plant such as cannabis, an initial step of the process provides a low-temperature, robust essential oil/terpene capture that also dehydrates and decarboxylates the starting product—fresh raw cannabis—by means of a vacuum-assisted microwave distillation process. By doing the terpene capture under vacuum distillation temperature may be kept low. The low distillation temperature maximizes yields of thermally-sensitive components such as terpenes and cannabinoids. The process includes additional steps of: extract cannabinoids from the dehydrated cannabis to produce a crude extract via a supercritical CO2 extraction process; purify crude extract of fats, lipids, plant material; and distill relevant cannabinoids from the purified crude extract via a wiped-film process. Selected terpenes and cannabinoids are then recombined in predetermined proportions to achieve extracts of unusual purity and zo having targeted therapeutic profiles.

BACKGROUND Technical Field

The present disclosure relates to methods for preparing extracts ofbotanical products. More particularly the present disclosure relates tomethods for preparing a purified extract from fresh cannabis.

Background Information

A plant medicine's therapeutic activity is attributed to the activeconstituents it contains. Although there are examples that show theactivity of C. Sativa has been linked to specific chemical species, itis also true that the plant's medicinal affect is due to one or morecombinations of constituents acting in concert.

Cannabis contains approximately 500 natural compounds. The two classesof compounds of greatest medicinal value are terpenes and cannabinoids.While cannabis may contain literally hundreds of terpenes, only a fewhave caught the interest of researchers and practitioners, among them:myrcene, linalool, limonene, humulene, pinene and caryophyllene. Untilrecently, it was thought that terpenes functioned mostly to givecannabis strains their characteristic flavors and aromas. Because ofthis, it was thought that, in preparing extracts, it wasn't necessary tobe concerned about terpene content in a final product because theterpenes didn't appear to be important to the medicinal effect of theproduct.

Recent research has revealed that terpenes play a much greater role inthe effect of a particular cannabis strain than originally thought. Ithas been found, for example, that in many situations, the interactionbetween a terpene molecule and a cannabinoid molecule is determinativeof the final effect of the relevant strain, with the terpene, in effect,regulating the medicinal action of the cannabinoid. Thus, a newappreciation is developing for terpenes' contribution to the medicinaleffect produced by a particular cannabis strain.

Over 100 cannabinoids have been identified in cannabis, some of whichare psychoactive. Of the cannabinoids, the molecules most studied may betetrahydrocannabinol (THC) and cannabidiol (CBD), the two cannabinoidsaccounting for the largest portion of the plant's extract. While THC mayaccount for more than 20% of extract volume in a high-THC strain, CBDlevels of over 4% are considered to be high. Recent research has shownCBD to have analgesic, anti-inflammatory, and anti-anxiety propertieswithout the psychoactive effects associated with THC.

Current methods of preparing abstracts fail to appreciate the importanceof terpenes to the quality and efficacy of the final product. Further,the cannabinoid yield from conventional methods tends to be sub-optimal.Additionally, the time required for zo conventional methods places alimit on the amount of extract that can be produced in an economicmanner.

SUMMARY

In a multi-step process for selectively purifying variouspharmacologically-relevant components of a source plant such ascannabis, an initial step of the process provides a low-temperature,robust essential oil/terpene capture that also dehydrates anddecarboxylates the starting product—fresh raw cannabis—by means of avacuum-assisted microwave distillation process. By doing the terpenecapture under vacuum distillation temperature may be kept low. The lowdistillation temperature maximizes yields of thermally-sensitivecomponents such as terpenes and cannabinoids.

The process includes additional steps of:

-   -   extract cannabinoids from the dehydrated cannabis to produce a        crude extract via a solvent extraction process;    -   purify crude extract of fats, lipids, plant material via a        winterization process;    -   distill relevant cannabinoids from the purified crude extract        via a wiped-film process.        Selected terpenes and cannabinoids are then recombined in        predetermined proportions to achieve extracts of unusual purity        and having targeted therapeutic profiles.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides a block a diagram of a process for preparing a purifiedextract from raw, fresh cannabis;

FIG. 2 provides a block diagram of a sub-process for extracting naturalessential oils from raw fresh cannabis;

FIG. 3 provides a diagram of a system for extracting natural essentialoils from raw fresh cannabis;

FIG. 4 provides a block diagram of a sub-process for extracting relevantcannabinoids from dehydrated cannabis;

FIG. 5 provides a diagram of a system for extracting relevantcannabinoids from dehydrated cannabis;

FIG. 6 provides a block diagram of a sub-process for refining a cannabisextract; and

FIG. 7 provides a block diagram of a sub-process for preparing adistillate from refined cannabis extract.

DETAILED DESCRIPTION

In a multi-step process 100 for selectively purifying variouspharmacologically-relevant components of a source plant such ascannabis, an initial step 102 of the process provides a low-temperature,robust essential oil/terpene capture that also dehydrates anddecarboxylates the starting product—fresh raw cannabis—by means of avacuum-assisted, gravity-assisted microwave distillation process. Bydoing the terpene capture under vacuum, distillation temperature may bekept low. The low distillation temperature maximizes yields ofthermally-sensitive components such as terpenes and cannabinoids.

The process includes additional steps of:

-   -   extract cannabinoids from the dehydrated cannabis to produce a        crude extract via a solvent-mediated extraction process 104;    -   purify crude extract of fats, lipids, plant material 106; and    -   distill relevant cannabinoids from the purified crude extract        via a wiped-film process 108. Selected terpenes and cannabinoids        are then recombined in predetermined proportions to achieve        extracts of unusual purity and having targeted therapeutic        profiles.

Terpene Distillation: Rapid Material Dehydration and CannabinoidDecarboxylation in a Single Process

For the initial distillation, a vacuum assisted microwavehydro-distillation (VAMHD) process is employed to rapidly dehydratefresh plant material at significantly lower temperatures than normallypossible with conventional processes, distilling the terpenes anddecarboxylating the cannabinoids contained in the plant material.

Conventionally, great emphasis is placed on drying cannabis slowly andgradually to preserve the terpene and cannabinoid content. Cut stems ofcannabis are typically hung or the buds are trimmed and laid out ondrying racks in climate-controlled environments. This drying/curingprocess can take up to four weeks. As part of an industrial-scaleprocess, the time and space requirements for such gradual drying andcuring add significantly to the manufacturing cost of the final product.

There exist high-speed methods of drying. Oven drying and convectiondrying have been used to shorten the time required to dry cannabis.Significant economies of time have been achieved with such speed-dryingmethods. But the high temperatures required adversely affect the terpeneand cannabinoid content, resulting in an inferior zo quality finalproduct.

Microwave drying has also been used. But it is thought that microwavedrying seriously compromises the concentration of psychoactivecomponents in the cannabis, resulting in an inferior-quality finalproduct.

After cannabis has been dried, it must be decarboxylated to activate thepsychoactive components. The main cannabis-derived cannabinoids comefrom related cannabinoid acids, which are 2-carboxylic acids, composedof a carboxyl group linked at the alpha carbon of the main cannabinoidgroup. While cannabinoid acids do have some therapeutic uses, in orderto produce the psychoactive effect for which cannabis is so highlyvalued, the raw cannabinoid acids must be decarboxylated, usuallythrough heating, to remove the carboxyl (—COON) functional group at thealpha carbon to form cannabinols or cannabidiols. Conventionally,cannabis is decarboxylated by heating the raw cannabis to approximately200° F. (−93° C.) for approximately one hour. While the prolongedexposure to high temperature converts the cannabinoids to abiologically-active form, it also has the unfortunate effect ofsignificantly decreasing cannabinoid concentration because of thevulnerability of the cannabinoid molecule to thermal degradation.Furthermore, this step allows the achievement of greater purity in eachof the downstream processes described herein below.

Lower temperatures may be used for decarboxylation, but the processproceeds much more slowly. In fact, cannabis can be decarboxylatedmerely by allowing it to cure at room temperature for an extended periodof time—several weeks, for example. Thus, an industrial-scale produceris faced with choosing between a time-intensive process and one thatadversely affects the quality of the end product.

The process herein described utilizes vacuum-assisted microwave hydrodistillation (VAMHD) to dry and decarboxylate the fresh plant material,which allows the it to be rapidly dehydrated and decarboxylated atsignificantly lower temperatures of approximately 10-50° C., thuspreserving the terpene and cannabinoid profile of the original material,while saving approximately 10 days over the industry drying standard.

FIG. 2 shows a sub-process of terpenes/essential oil capture 200. Asshown in FIG. 2, the starting material for the vacuum-assisted microwavehydro-distillation (VAMHD) is raw cannabis—that is, freshly-harvestedplant material that has not had an opportunity to dry.

Hydro distillation is an alternative method of extracting essential oilsto steam distillation. In hydro distillation, rather than having steampass through the plant material from which the essential oil is to beextracted, the plant material is soaked in water for a period of time,after which the mixture of water and plant material is heated. Thevolatile essential oil is carried away in the steam, condensed andseparated.

The fresh plants may be initially processed by being shredded and/orfinely chopped 202. Shredding the plant allows it to be closely packedinto the distillation vessel 304 and allows uniform exposure of thefresh plant material to the heat and the reduced air pressure created bythe vacuum 312.

After shredding, the raw plant material may be frozen 204. Inembodiments, the plant material may be flash-frozen by exposing it toliquid nitrogen. In embodiments, the plant material may be flash-frozenby exposing it to dry ice. The frozen cannabis may then be broken upinto small pieces and transferred to a vessel suitable for heating inthe microwave. In embodiments, a round-bottom flask, such as a 3-literround-bottom flask, may be used.

Additionally, the fresh plant material may be placed in the distillationvessel 304 without being previously frozen.

If dried plant material is being used, an amount of water may then beadded to the distillation vessel 304 containing the raw plant materialto prepare the mixture.

One of ordinary skill will appreciate that the process is readily scaledand that the choice of vessel is a function of the process scale.

The vessel containing cannabis/water mixture may then be placed into amicrowave oven under vacuum 312. In embodiments, the vessel containingthe frozen cannabis is then heated for a predetermined time period. Thelength of the time period is a function of the wattage of the microwaveoven, the size of the vessel and the quantity of cannabis in the vessel.In embodiments, a 3-liter vessel packed with frozen zo cannabis may beheated on ‘high’ in a 1000 watt microwave oven for 60 minutes 206.

In embodiments, the vessel may be inverted to achieve an optimally evenmicrowave distribution, thus avoiding the common problem in microwaveovens of hot spots and cold spots. In this way, the essential oil yieldfrom the distillation may be optimized.

Throughout the heating period, the vessel contents emit a vapor thatincludes an aqueous phase and an oil phase, containing the essential oilfrom the cannabis, containing a high concentration of terpenes 208.

As indicated above, the end products of the distillation sub-process arecannabis essential oil and dried, decarboxylated cannabis. The dried,decarboxylated cannabis may then undergo a secondary solvent extractionto recover the biologically active cannabinoids 210.

FIG. 3 provides a diagram of a vacuum-assisted microwave dehydrationsystem 300 with which the sub-process of FIG. 2 may be carried out. Asshown, the system 300 includes a microwave heating unit 302. Theexemplary embodiment of FIG. 3 shows a conventional microwave oven 302as would be found in many households and laboratory settings. Dependingon the process scale, the microwave oven 302 could be a larger,higher-power, industrial-scale unit.

A distillation vessel 306 is packed with cannabis 304 prepared asdescribed herein above and placed in the microwave oven 302. Awater-chilled condenser 308 is coupled with the neck of the distillationvessel 306. It should be noted that the distillation vessel 307 and thecondenser 308 are shown in an inverted position. In embodiments, thesub-process 200 is gravity-assisted. As the cannabis 304 heats, theessential oil and the water form a mixed vapor. It will be appreciatedthat performing the process 200 under vacuum conditions considerablyreduces the temperature at which the essential oil and water within thedistillation vessel are converted to their vapor phases. The mixedvapor, due to the vacuum conditions, is promptly evacuated from thevessel 306, being drawn from the vessel 306 into the condenser 308. Byexploiting the effect of gravity, evaporated water and essential oil areseparated from zo cannabis 304 in the vessel 306 much more rapidly thanwould be possible without the gravity assist. Furthermore, the gravitygreatly assists drying of the cannabis to prepare for the followingsub-process. The vacuum conditions, supplemented by the gravity assist,also allow recovery of a greater quantity of essential oil, having aricher concentration of terpenes.

By using a gravity assist to continuously evacuate essential oil/waterfrom the distillation vessel, it is possible to dry and carboxylate thecannabis. In fact, at the end of the distillation, the cannabis 306remaining in the vessel 306 is nearly completely dried, needing only ashort exposure to the air at room temperature to finish drying.Laboratory testing of the extract reveals that the cannabinoid fractionof the extract is 97% decarboxylated cannabinoids.

Vacuum conditions are maintained within the system 300 by means of avacuum generator 312.

An oil/water separator 310 facilitates separation of the essential oil316 and the aqueous component 318 into separate phases. The essentialoil then accumulates in the separator 310, while the aqueous component318 is drained into a separate vessel 314.

Labor Secondary Solvent Extraxtion

As in FIG. 4, a further step in the process involves a secondary solventextraction 400 for relevant cannabinoids. This process may utilize anynumber of hydrocarbon solvents having a polarity sufficient forcannabinoid extraction including, but not limited to, methanol, ethanol,isopropanol, hexane, pentane, butane, propane, naphtha, chloroform.Supercritical CO2 may also be used for the solvent extraction.

While naphtha or petroleum ether extract may well be the most effectivesolvents for most cannabinoids, concerns about toxic solvent residues inproducts have caused practitioners to look for additional solutions. Inembodiments, supercritical CO2 extraction is used to produce a crudeextract containing the relevant cannabinoids from the dried,decarboxylated cannabis because it is an efficient, non-toxic andnon-flammable process.

Extraction relies on the phenomenon of diffusion, in which the solventdiffuses into the solid plant matter and the target material diffusesfrom the plant matter into the solvent. Diffusion may occur at differentrates with different solvents. For example, extraction with hydrocarbonsolvents may require a period of hours.

Diffusion may occur faster when using supercritical fluids than withhydrocarbon solvents, allowing extraction to proceed more rapidly,taking an hour or less, depending on the type of product, the quantityand the equipment. While supercritical CO2 extraction provides certainadvantages, it is also a much more costly process.

Thus, a sub-process for extracting cannabinoids from dried cannabis 400may include steps of:

-   -   placing an amount of dried cannabis in an extraction chamber        402;    -   introducing an amount of solvent to the extraction chamber 404;    -   allowing the solvent to remain in contact with the dried        cannabis for a predetermined period of time 406;    -   purging the solvent from the extraction chamber after the        predetermined period of time has elapsed 408; and    -   retrieving accumulated extract from the collection vessel 410.        Supercritical CO2 extraction

A supercritical fluid can diffuse through a solid as a gas does, and canalso dissolve materials as a liquid does. In addition, close to thecritical point, small changes in pressure and/or temperature lead torelatively large changes in density of the supercritical fluid, allowingmany properties of a supercritical fluid to be adjusted or “tuned” tofit the application. For these reasons, supercritical fluids, such assupercritical CO2, can substitute for hydrocarbon solvents in manyindustrial and laboratory processes, such as cannabinoid extraction.

Referring now to FIG. 5, shown is an exemplary system 500 for solventextraction. The system 500 may include a solvent supply 502, typicallyin the form of a zo supply tank containing solvent or compressed CO2. Aline may conduct the solvent from the supply 502 to a reservoir 504. Thesolvent then proceeds to a pump 506 which pumps the solvent to a heatingzone 510, where it is heated to the lowest temperature conducive todissolution of the cannabinoids in the solvent. Using the lowesteffective temperature lessens the possibility of diminished yield due tothermal damage to the cannabinoids.

After passing through a heater coil 508, the heated solvent passes intoan extraction vessel 512. In the extraction vessel 512, the solventdiffuses through the plant matter of the cannabis and dissolves thetarget material to be extracted—in this case, the cannabinoids. Thedissolved cannabinoids and lipids are cleared from the extraction vessel512 into a collection vessel 514 by means of a metering valve.

The product resulting from the solvent extraction is a crude cannabisextract containing a high concentration of cannabinoids, with some sideproducts, such as lipids and pigments from the cannabis.

Subsequent refinement steps may be a function of the extraction methodutilized. Supercritical CO2 extractions may be followed by a winterizingstep, described in detail, herein below, which leverages ethanol (ETOH)to separate pure cannabinoids and terpenes from other byproductsisolated during extraction. This process serves to pull out undesiredmaterial in advance of downstream processing.

A hydrocarbon solvent-based extraction, due to the polarity of thesolvent, does not incorporate the plant waxes and fats found in a CO2extract. Thus, an activated carbon filtration process may be used toremove undesirable compounds like chlorophyll and other pigments.

Winterization

As above, the product of the secondary extraction is a crude extracthaving a high concentration of cannabinoids. In addition to thecannabinoids, the extract may also contain residual terpenes that werenot extracted during the initial process. The zo crude extract may alsocontain a number of undesirable components such as lipids, waxes,pigments, or other such plant material. An additional refinement processserves to greatly reduce the level of these undesirable components andprepare the crude extract for downstream processing.

Many of the impurities remaining in the extract may be longer-chainhydrocarbons having a relatively high melting point. Thus, a refiningprocedure to remove the long-chain impurities involves dissolving thecrude extract in ethanol (ETOH), freezing the ETOH solution andfiltering it to remove the precipitated long-chain impurities.Additionally, treating the crude extract with ETOH, freezing andfiltering have the added benefit of removing more of the residualterpenes and further concentrating the cannabinoid fraction.

The initial step in the winterization process 600 involves re-dissolvingthe crude extract in ETOH 602. In embodiments, the ETOH may be at roomtemperature. In embodiments, to facilitate dissolving the crude oil inthe ETOH, the ETOH may be heated to a temperature slightly above roomtemperature (RT), for example 30° C. While a lower temperature helps toensure a higher cannabinoid concentration in the final product, incertain applications, it may be desirable to heat the ETOH considerablyabove RT, for example, as high as 45° C.

In embodiments, the crude oil and the ETOH may be combined in apredetermined ratio, for example 10 ml of ETOH for each gram of extract.Choice of the ration of oil to ETOH is driven by a number of factors,such as lipid and cannabinoid concentration of the starting material.

After the ETOH and the crude oil are combined, the mixture may bestirred, either manually, using a laboratory implement such as aspatula, or by using an automated stirring device, such as a magneticstirrer. After the crude oil is fully dissolved in the ETOH, thesolution is held at an approximate temperature of −20° C. for a periodof approximately 24 hours 602. The solution is then passed through afilter having a 25-micron pore size to remove precipitated solids.

The solution may again be chilled to −20° C., and held for 24 hours 604.It will be appreciated that freezing the solution for an extended periodresults in a liquid layer—the extract/ethanol solution and a layer ofprecipitated solids. Found within the precipitated solids are the plantmatter and solidified lipid impurities that are to be eliminated fromthe solution. Following the 24-hour freeze, the solution is passedthrough a 25-micron filter.

The solution may again be refrozen to −20° C. and held for 24 hours 606,after which it may be passed through a 2.5 micron filter.

The solution may again be refrozen to −20° C. and held for 24 hours 608,after which it may be passed through a 0.2 micron membrane filter.

It will be appreciated that the duration of the freezing periods may bereduced by subjecting the solution to lower temperatures. For example,if the solution is frozen using, for example, dry ice, the freezing timemay be reduced. The freezing point of the solvent and/or the solute,would, of course, impose a lower limit on the freezing temperature.

Even after being thoroughly treated in this manner, there may remainenough chlorophyll in the solution to give it a green hue. Inembodiments, the solution may, for example, be treated by exposing tosunlight or UV radiation, washing with an appropriate solvent or by anactivated carbon filtration. Removing the chlorophyll, however, mayadversely affect cannabinoid concentration in the final product 608.

The waxes removed from the oil as a result of winterization may bediscarded, however they may also be recovered and diverted into otherprocesses/products, skin care additives or personal lubricants, forexample.

Terpenes removed as a result of winterization may be recovered andrecombined with the terpenes produced as a result of the primaryextraction for use in other products, or for recombining with thecannabinoids at predetermined levels to produce an extract having atargeted therapeutic profile 610.

After the waxes, pigments and plant material are removed during thewinterization process, the ETOH may be purged from the solution 610,leaving a zo winterized extract. In embodiments, using a vacuum and avacuum oven, the boiling point of the ETOH can be reduced to well belowroom temperature. In embodiments, the ETOH may be purged using a rotaryevaporator.

Wiped-Film Distillation

The final stage of the disclosed method utilizes a wiped-filmdistillation technique to purify the winterized material into adistillate containing highly concentrated cannabinoids in ratios similarto those found in the original plant material. Purity is typicallygreater than 98% total cannabinoids and may be as high as 99.8% purecannabinoids.

The winterized extract typically has a thick, syrupy consistency.Additionally, because of the high cannabinoid content, the extract isvery heat-sensitive. Thus, it is desirable, at all stages of processingto minimize exposure of the extract to higher temperature. Aconventional still-pot distillation provides a number of disadvantagesfor a heat-sensitive product such as the presently-described extract.Chief among these is the long residence time necessitated by theconventional pot distillation. As we have indicated, the extendedthermal exposure in a batch process system degrades the quality of theextract. In particular, exposure of the cannabinoids in the extract tothe extended heat in a conventional pot distillation system causes asignificant drop in the cannabinoid concentration of the final product.

Another disadvantage of a conventional pot distillation system is that alarge volume of product is lost due to the extract fouling the equipmentas a result of its sticky, viscous consistency. As a matter of fact, thecannabis extract can foul the equipment so badly that it has to bediscarded frequently.

Another disadvantage of a conventional pot distillation approach is thevery slow rate of processing. The speed with which a quantity of extractcan be distilled using a wiped-film approach produces a distinctbusiness advantage for commercial producers.

Finally, as indicated above, the wiped-film approach allows theproduction of an extract of exceptional purity and potency.

In embodiments, this final distillation may utilize a wiped-filmevaporator and vacuum distillation. In embodiments, this finaldistillation may utilize a short-path wiped-film evaporator having acondenser that is located inside the evaporator body.

A wiped film evaporator can provide the short residence time needed andan open, low pressure drop configuration, allowing continuous, reliableprocessing of heat sensitive, viscous, or fouling materials such ascannabis extract, without product degradation.

In a wiped-film evaporator (WFE), the product is fed into the top of acylinder and evenly dispersed by a distributor. Heat is applied to theexterior surface of the cylinder, for example by a heated jacket. As theliquid film runs down the inside surface of the cylinder, a rotatingwiper system spreads, agitates and moves the product down and off of theheated cylinder wall in a matter of seconds. Heat transfer under vacuumconditions causes the product to evaporate at a greatly reducedtemperature. Evaporated product is allowed to pass through aliquid-vapor separator, while droplets of unevaporated product arethrown back to the heated surface. The vapor condenses on a condenserenclosed within the cylinder and exits the WFE through a distillateoutlet.

In embodiments, condensation may take place in a condenser locatedoutside of the evaporator.

The wiped-film distillation may be carried out using any of a number ofcommercially-available wiped-film, short-path stills. For example, in anembodiment, the wiped-film distillation may be carried out using a stillsuch as the Pope Wiped-Film Molecular Still, manufactured by POPESCIENTFIC, Inc., Saukville, Wisc.

In embodiments, the wiped-film distillation may be carried out using astill such as a Thin-Film, Short-Path Evaporator manufactured by LCI,Inc. Charlotte, N.C.

In embodiments, the wiped-film distillation may be carried using a stillsuch as a zo Short-Path Distillation Plant manufactured by ROOTSCIENCES, Inc., Seattle, Wash.

Any of the foregoing systems are vacuum distillation systems that embodythe use of a wiped-film (aka “thin-film”) evaporator having anincorporated condenser, which greatly reduces the amount of time theproduct is exposed to heat to no more than a few seconds. The provisionof a short path between the evaporator and the condenser allows thepressure within the system to be kept at a level that approximates thevapor pressure of the cannabinoid fraction, allowing the cannabinoidfraction to evaporate rapidly with minimal application of heat, therebypreserving the cannabinoids.

While several commercially available systems have been described hereinabove, one of ordinary skill will readily realize that a system forwiped-film distillation system embodying the same operative principlesas the named systems may be obtained from other sources or it may beconstructed from readily available components, either of whichembodiments are entirely consistent with the scope of the presentdisclosure and the attached claims.

FIG. 7 provides a block diagram of a sub-process for distilling acannabis extract.

As described herein above, the sub-process 700 may include at least thesteps of:

-   -   introducing liquid extract into a wiped-film evaporator (WFE)        under vacuum conditions 702;    -   dispersing the liquid extract on the heated interior surface of        the WFE by means of a wiper system 704;    -   separating extract evaporated by a combination of vacuum        conditions and heat transfer from liquid extract 706;    -   condensing evaporated extract 708; and    -   collecting distillate 710.

The methods for preparing concentrated extracts of cannabis may bedeployed at any scale. Small producers may utilize them to producemilliliter amounts of product. Furthermore, the process may be scaledand used by commercial producers to produce bulk quantities.

It will be appreciated that many products may result from the methodsand zo approaches herein described. One product is a highly-purified,terpene-rich cannabis essential oil. A second product is a cannabisextract having a cannabinoid concentration that may exceed 99%. Manyadditional products may result from recombining the essential oil andcannabinoids in various proportions to produce extracts having a varietyof medicinal effects. Furthermore, as a result of the ability tofine-tune the extraction sub-process by varying temperature andpressure, the extraction procedure may be modified to favor onecannabinoid fraction over another. Thus, the relative concentration ofdifferent cannabinoid fractions can be varied in the final extract.

Additionally, the by-products of the winterization process maythemselves be diverted into other products, for example personallubricants and skin-care products.

Moreover, the hydrosol resulting from the initial distillation mayitself serve as the basis for additional products.

While the above methods have been described in connection withproduction of cannabis extract, the same methods may be deployed toisolate and purify components of all sorts of culinary, aromatic andmedicinal herbs such as lavender, sage and rosemary.

While the foregoing written description enables one of ordinary skill touse the methods herein described, those of ordinary skill willunderstand and appreciate the existence of variations, combinations, andequivalents of the specific embodiments, methods, and examples herein.The specification should therefore not be limited by the above describedembodiments, method, and examples, but by all embodiments and methodswithin the scope and spirit of the attached claims.

1. A method for preparing purified extracts from raw cannabis comprising: A. distilling a terpene-rich essential oil from a water/raw cannabis mixture prepared by heating the raw cannabis/water mixture under gravity-assisted, vacuum conditions in a microwave oven at a predetermined power level for a predetermined period of time; B. followed by preparing a cannabinoid-rich crude extract from dried, decarboxylated cannabis resulting from A by exposing the dried, decarboxylated cannabis to a solvent and allowing a resulting extract to accumulate in a collection vessel as the solvent is purged; C. followed by refining the crude extract to remove impurities; and D. followed by preparing a purified extract from the refined extract by distilling the refined extract in a wiped-film evaporator under vacuum conditions.
 2. The method of claim 1, wherein raw cannabis comprises fresh plant material that has not had an opportunity to dry.
 3. The method of claim, wherein A further comprises at least one of: shredding and/or chopping the raw cannabis; soaking the raw cannabis in water; freezing the raw cannabis; packing the raw cannabis into a distillation vessel.
 4. The method of claim 1, wherein A further comprises: heating a distillation vessel containing raw cannabis in a microwave oven under vacuum conditions; inverting the distillation vessel as the cannabis is being heated; heating the cannabis in the microwave oven for a period of 60 minutes; heating the cannabis in a 1000-watt microwave oven at ‘high’ power.
 5. The method of claim 1, wherein A further comprises: condensing vapor produced by heating the cannabis into a mixture of terpene-rich cannabis essential oil and water separating the terpene-rich essential oil from the heated raw cannabis/water mixture; wherein heating in the microwave dries and decarboxylates the cannabis.
 6. The method of claim 1, wherein the solvent comprises one of: methanol; ethanol; isopropanol; hexane; pentane; butane; propane; naphtha; and chloroform.
 7. The method of claim 6, wherein C further comprises: filtering the crude extract through activated carbon to remove undesirable components.
 8. The method of claim 1, wherein the solvent comprises at least one of: super-critical CO2.
 9. The method of claim 1, wherein B further comprises: placing an amount of dried cannabis in an extraction chamber; introducing an amount of solvent to the extraction chamber; allowing the solvent to remain in contact with the dried cannabis for a predetermined period of time; allowing the solvent to evaporate after the predetermined period of time has elapsed; and retrieving accumulated extract from the collection vessel.
 10. The method of claim 9, wherein the predetermined period of time is approximately one hour.
 11. The method of claim 8, wherein B further comprises: varying temperature and/or pressure of the solvent to target an identified cannabinoid fraction for extraction.
 12. The method of claim 1, wherein C further comprises: preparing a refined extract from the crude extract by dissolving the crude extract in a solvent and iteratively: chilling a resulting solution to a temperature of approximately −20° C. for a period of at least 24 hours; and filtering out solid elements formed in the chilled solution;
 13. The method of claim 1, wherein C further comprises: dissolving the crude extract in ethanol; alternately chilling the extract/ethanol solution to an approximate temperature of −20° C. for a period of approximately 24 hours and filtering the extract to remove precipitated solids; wherein each said filtering is through a filter having a smaller pore size than a preceding filter.
 14. The method of claim 13, wherein the frozen solids comprise undesirable compounds including lipids, waxes, pigments, and plant matter.
 15. The method of claim 13, wherein C further comprises: purging ethanol from the extract/ethanol solution.
 16. The method of claim 13, wherein C further comprises: treating the chilled, filtered extract/ethanol solution to remove pigments.
 17. The method of claim 16, wherein treating the chilled, filtered extract/ethanol solution to remove pigments comprises one of: filtering through activated charcoal; and treating with UV light and/or sunlight.
 18. The method of claim 1, wherein D further comprises: introducing the refined extract into a wiped-film evaporator (WFE) under vacuum conditions; dispersing the refined extract on the heated interior surface of the WFE by means of a wiper system; separating the refined extract evaporated by a combination of vacuum conditions and heat transfer from liquid extract; condensing evaporated extract; and collecting condensed distillate.
 19. The method of claim 18, wherein condensing is performed by one of: an enclosed condenser; and a condenser located outside of the WFE.
 20. The method of claim 1, further comprising: recombining the terpene-rich essential oil and the purified extract in predetermined portions to create products having targeted medicinal effects. 